Nanosized Effect on Electronic/Local Structures and Specific Lithium-Ion Insertion Property in TiO2—B Nanowires Analyzed by X-ray Absorption Spectroscopy

摘要

TiO_2-B nanowires were prepared by hydrothermal reaction, and the nanosized effect on lithium-ion insertion was investigated by using X-ray absorption spectroscopy (XAS). On the basis of the results of O K-edge X-ray absorption near-edge structure (XANES) of TiO2—B with various particle sizes, it was suggested that the surface of TiO2—B has local and electronic structures being different from the bulk, and the band energy of surface of TiO2—B was lower than that of the bulk. The band vended structure, which is called the space charge layer (SCL), makes lithium-ion insertion in TiO2—B smooth because the local structure of the SCL is maintained during the lithium-ion insertion, which is shown by Ti K-edge extended X-ray absorption fine structure (EXAFS) spectroscopy. It is suggested that control of the SCL, that is the nanosized effect, is a new design concept for achieving higher rate capability.